scholarly journals Application and Comparison of Two Chlorine Decay Models for Predicting Bulk Chlorine Residuals

2016 ◽  
Author(s):  
Sonia Al Heboos ◽  
István Licskó
Keyword(s):  
Chlorine Decay ◽  
Chlorine Residuals

scholarly journals Integrating booster chlorination and operational interventions in water distribution systems

2018 ◽  
Vol 20 (5) ◽  
pp. 1025-1041
Author(s):  
Denis Nono ◽  
Innocent Basupi ◽  
Phillimon T. Odirile ◽  
Bhagabat P. Parida
Keyword(s):  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Water Age ◽  
Nsga Ii ◽  
Chlorine Disinfection ◽  
Periodic Monitoring ◽  
Chlorine Decay ◽  
Booster Chlorination ◽  
Chlorine Residuals

Abstract Booster chlorination reduces the risks associated with conventional disinfection such as high chlorine residuals near water treatment plants and low chlorine residuals at remote parts of water distribution systems (WDSs). Network operational interventions have a significant influence on water age and chlorine decay in WDSs. In this study, an integrated booster chlorination method is developed to obtain optimal designs that reduce the risks associated with conventional disinfection in WDSs. The method integrates booster chlorination with network operational interventions to reduce water age and improve chlorine residuals in WDSs. A multi-objective booster optimisation problem is formulated based on risks associated with chlorine disinfection and solved using a non-dominated sorting genetic algorithm (NSGA-II) and the EPANET hydraulic and water quality solver. The proposed methodology was tested in the Phakalane WDS in Botswana. The integrated booster disinfection method significantly improves chlorine residuals in a WDSs with lower mass and cost of chlorine than conventional disinfection. Furthermore, the study indicates that integrated booster chlorination designs are influenced by changes in network conditions such as water demand and chlorine decay coefficients. Therefore, periodic monitoring of these parameters is required to ensure that the acceptable performance of chlorine boosters in WDSs is maintained.

MODELLING CHLORINE DECAY IN DRINKING WATER MAINS

2008 ◽  
Vol 7 (6) ◽  
pp. 737-741 ◽  
Author(s):  
Diana Robescu ◽  
Nicolae Jivan ◽  
Dan Robescu
Keyword(s):  
Drinking Water ◽  
Water Mains ◽  
Chlorine Decay

Nitrate and chloride formation in chloramination

1994 ◽  
Vol 30 (9) ◽  
pp. 101-110
Author(s):  
V. Diyamandoglu
Keyword(s):  
Kinetic Model ◽  
Analytical Method ◽  
Kinetic Data ◽  
Experimental Results ◽  
Mass Balances ◽  
Time Profiles ◽  
Slow Decay ◽  
Concentration Time ◽  
End Products ◽  
Chlorine Residuals

The formation of nitrate and chloride as end-products of chloramination (combined chlorination) was investigated at pH ranging between 6.9 and 9.6 at 25°C. The experimental results comprised concentration-time profiles of combined chlorine residuals along with nitrate and chloride. Nitrite, if present, was always below the detectibility limit of the analytical method used (25 ppb). Mass balances on chlorine species depicted that chloride formed during the slow decay of combined chlorine residuals does not account for all the chlorine lost. This substantiates the formation of other reaction end-products which are yet to be identified. A kinetic model for chloramination is proposed based on the kinetic data obtained in this study.

Application of two approaches to model chlorine residuals in Severn Trent Water Ltd (STW) distribution systems

1997 ◽  
Vol 36 (5) ◽  
pp. 317-324 ◽  
Author(s):  
M.J. Rodriguez ◽  
J.R. West ◽  
J. Powell ◽  
J.B. Sérodes
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Treatment Plant ◽  
Residual Chlorine ◽  
Ann Model ◽  
Order Model ◽  
First Order ◽  
Chlorine Decay ◽  
Artificial Neural Network Ann ◽  
Key Parameter

Increasingly, those who work in the field of drinking water have demonstrated an interest in developing models for evolution of water quality from the treatment plant to the consumer's tap. To date, most of the modelling efforts have been focused on residual chlorine as a key parameter of quality within distribution systems. This paper presents the application of a conventional approach, the first order model, and the application of an emergent modelling approach, an artificial neural network (ANN) model, to simulate residual chlorine in a Severn Trent Water Ltd (U.K.) distribution system. The application of the first order model depends on the adequate estimation of the chlorine decay coefficient and the travel time within the system. The success of an ANN model depends on the use of representative data about factors which affect chlorine evolution in the system. Results demonstrate that ANN has a promising capacity for learning the dynamics of chlorine decay. The development of an ANN appears to be justifiable for disinfection control purposes, in cases when parameter estimation within the first order model is imprecise or difficult to obtain.

A Variable Rate Coefficient Chlorine Decay Model

2009 ◽  
Vol 43 (2) ◽  
pp. 408-414 ◽  
Author(s):  
Philip M. R. Jonkergouw ◽  
Soon-Thiam Khu ◽  
Dragan A. Savic ◽  
Dan Zhong ◽  
Xiu Q. Hou ◽  
...  
Keyword(s):  
Rate Coefficient ◽  
Variable Rate ◽  
Decay Model ◽  
Chlorine Decay

Time to Move on From Measuring Chlorine Residuals With Outdated Methods

Opflow ◽  
2021 ◽  
Vol 47 (10) ◽  
pp. 6-7
Author(s):  
Steve Deem ◽  
Nancy Feagin ◽  
Krista Chavez
Keyword(s):  
Chlorine Residuals

Chlorine Decay Modeling in the S. Giacomo Storage Tank, Napoli

WRPMD'99 ◽  
1999 ◽  
Author(s):  
C. Gualtieri ◽  
E. Mastrangelo ◽  
U. Potenza ◽  
G. Rotondo
Keyword(s):  
Storage Tank ◽  
Chlorine Decay

Dependency of bulk chlorine decay rates on flow velocity in water distribution networks

2003 ◽  
Vol 3 (1-2) ◽  
pp. 209-214 ◽  
Author(s):  
J. Menaia ◽  
S.T. Coelho ◽  
A. Lopes ◽  
E. Fonte ◽  
J. Palma
Keyword(s):  
Drinking Water ◽  
Flow Velocity ◽  
Distribution Systems ◽  
Distribution Networks ◽  
Decay Rates ◽  
Decay Kinetics ◽  
Decay Rate Constant ◽  
Chlorine Residual ◽  
Chlorine Decay ◽  
Static Conditions

Understanding chlorine residual decay kinetics and the factors that influence them are essential for such current tasks as siting chlorination facilities, dosage optimisation, choice of sampling locations and frequencies, and general design and operational control of drinking water networks, increasingly accomplished with the help of simulation models. Available constants for bulk chlorine decay are typically determined under static conditions. However, as for all fast reactions in water flows, chlorine consumption rates in drinking water pipes may be influenced by the existing mixing regimes, a function of flow turbulence, which is primarily controlled by flow velocity and pipe diameter. Flow velocities vary greatly in space and time in water transmission and distribution systems; pipe diameters are seldom uniform. Although both variables are readily available in the currently available network analysis simulators that implement chlorine models, such variations are not accounted for. Instead, a single preset decay rate constant is generally used for describing chlorine residual consumption throughout an entire system. In addition to highlighting how negligible PVC pipe wall chlorine consumption is, as such, this paper presents experimental evidence of a significant correlation between pipe flow velocity and bulk chlorine decay rates, and proposes a simple but effective approach to implement this dependency in current simulators.

Chlorine decay and trihalomethane formation following ferrate(VI) preoxidation and chlorination of drinking water

Chemosphere ◽  
2017 ◽  
Vol 187 ◽  
pp. 413-420 ◽  
Author(s):  
Cong Li ◽  
Feng Luo ◽  
Feilong Dong ◽  
Jingguo Zhao ◽  
Tuqiao Zhang ◽  
...  
Keyword(s):  
Drinking Water ◽  
Chlorine Decay

An experimental study for chlorine residual and trihalomethane formation with rechlorination

2007 ◽  
Vol 55 (1-2) ◽  
pp. 307-313 ◽  
Author(s):  
J. Lee ◽  
D. Lee ◽  
J. Sohn
Keyword(s):  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Disinfection Byproducts ◽  
Correction Coefficient ◽  
Empirical Power ◽  
Chlorine Residual ◽  
Chlorine Decay ◽  
And Control ◽  
Large Distribution

Maintenance of adequate chlorine residuals and control of disinfection byproducts (DBPs) throughout water distribution systems is currently an important issue. In particular, rechlorination can be a powerful tool in controlling adequate chlorine residual in a large distribution system. The patterns of chlorine decay and formation of DBPs due to rechlorination are different from those of chlorination; chlorine decay is slower and trihalomethane (THM) formation is lower with rechlorination. The present study evaluates whether existing predictive models for chlorine residual and THM formation are applicable in the case of rechlorination. A parallel first-order decay model represents the best simulation results for chlorine decay, and an empirical power function model (modified Amy model) with an introduced correction coefficient (ϕ1, ϕ2) is more suitable to THM formation.

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